The present invention generally relates to the field of navigation systems for automotive vehicles. More particularly, the invention is directed to a system for providing driving directions to a user and a method of operating the system.
Vehicle operators need the ability to obtain accurate navigating directions from a current position without the difficulties of being connected to a service operator via a phone call. For example, being in continuous phone connection with an operator may contribute to reduced attentiveness to driving conditions. Likewise, operators at service centers need a system to quickly analyze the driver""s vehicle position to deploy relevant and accurate directions in the shortest time possible.
A number of navigation systems exist that provide driving instructions to a user or operator of a motor vehicle. In general, these systems fall into two categories: autonomous or stand-alone systems, and systems that involve a communication link to a server or human operator.
Most autonomous systems are relatively high-cost devices that are designed to be permanently installed into a vehicle. The devices include map information, typically stored on a CD-ROM, and a means to relay that information to a user in speech or images. Typically, these systems utilize a device to determine the position of the vehicle. Many current vehicle navigation systems use a Global Positioning System (GPS). GPS includes NAVSTAR GPS and its successors, Differential GPS (DGPS), or any other electromagnetic wave positioning system. Such a GPS system can be used to calculate distance and direction traveled. Other systems used to calculate vehicle position include various sensors attached to the vehicle to measure the progress of the vehicle relative to a previously known position. This method of dead reckoning, however, is susceptible to sensor error, and therefore requires expensive sensors for accuracy and dependability.
Many types of on-board vehicle navigation apparatus having the ability to give navigational instructions in speech form have been suggested for the driver""s convenience. With these types of on-board systems with oral navigation functions, a route from the current position to the destination is automatically determined based on the map data once the driver specifies the desired destination. When the vehicle approaches an intersection while traveling along the suggested route, an oral navigational instruction is given as to whether to turn right or left at the intersection.
Another example of an autonomous system includes the implementation of a database and navigation system based on a laptop computer platform. This system includes a GPS unit for providing a position of the laptop computer. Driving instructions are provided by a text to voice converter that converts the text driving instructions into a voice signal. The instructions are output by the computer at a time based on the position of the vehicle and a time period required to speak the directions.
Other prior art systems include a wireless communication device with which a vehicle occupant retrieves driving instructions from a service representative or operator. In such a system, however, the operator does not have a system to quickly analyze the vehicle position. Further, either the operator must stay in voice contact with the vehicle user to continuously relay instructions to the user or the user must record the directions and then refer to them. However, reference to the recorded directions during driving may contribute to a dangerous driving situation.
Accordingly, it would be desirable to have a relatively low-cost navigation system whereby the operator of a vehicle could obtain and refer to accurate directions in a convenient format that overcomes the disadvantages described above. In particular, one embodiment of the method and system of the present invention provides vehicle operators the ability to obtain accurate driving directions from a current driving location by downloading up-to-date route information from a computer-based server in an audible format and output in response to voice commands.